This application relates to devices and techniques that use magnetic resonance imaging (MRI) techniques.
Imaging through MRI techniques is well known and has been widely applied in imaging applications in medical, biological and other fields. In essence, a typical MRI technique produces an image of a selected body part of an object under examination by manipulating the magnetic spins in a body part and processing measured responses from the magnetic spins. MRI systems may include hardware to generate different magnetic fields for imaging, including a static magnetic field along a z-direction to polarize the magnetic spins, gradient fields along mutually orthogonal x, y, or z directions to spatially select a body part for imaging, and an RF magnetic field to manipulate the spins.
Currently, transit delays in an arterial spin labeling (ASL) experiment, such as Proximal Inversion with a Control for Off-Resonance Effect (PICORE), Flow-sensitive Alternating Inversion Recovery (FAIR), and pulsed continuous ASL (PCASL), refer to the time required for the labeled blood to arrive in the imaging slice. Knowledge of the transit delays is very important for conducting ASL experiments. Transit delay measurements include a series of separate ASL experiments acquired at several different post-labeling delays (PLD). Additional scans are usually needed to map T1 and blood magnetization (M0) for core blood flow (CBF) quantification. Such measurements are usually time-consuming and can be formidable overheads for ASL studies. The time requirement also makes the measurements highly sensitive to motion.